ISTANBUL - President Tayyip Erdogan said on Sunday that the final goal of a Turkish military incursion into Syria was not just to retake the city of al-Bab from Islamic State, but to cleanse a border region including Raqqa of the jihadists. 'The ultimate goal is to cleanse a 5,000-square-km area,' Erdogan told a news conference before his departure on an official visit to Bahrain, Saudi Arabia and Qatar. Turkey has long advocated a 'safe zone' for civilians in northern Syria cleared of Islamic State militants and the Kurdish YPG militia, but says such an area would need to be policed by a no-fly zone.